django/tests/migrations/test_writer.py

# encoding: utf8

from __future__ import unicode_literals

import datetime
import os

from django.apps import app_cache
from django.core.validators import RegexValidator, EmailValidator
from django.db import models, migrations
from django.db.migrations.writer import MigrationWriter
from django.test import TestCase
from django.utils import six
from django.utils.deconstruct import deconstructible
from django.utils.translation import ugettext_lazy as _


class WriterTests(TestCase):
    """
    Tests the migration writer (makes migration files from Migration instances)
    """

    def safe_exec(self, string, value=None):
        l = {}
        try:
            exec(string, globals(), l)
        except Exception as e:
            if value:
                self.fail("Could not exec %r (from value %r): %s" % (string.strip(), value, e))
            else:
                self.fail("Could not exec %r: %s" % (string.strip(), e))
        return l

    def serialize_round_trip(self, value):
        string, imports = MigrationWriter.serialize(value)
        return self.safe_exec("%s\ntest_value_result = %s" % ("\n".join(imports), string), value)['test_value_result']

    def assertSerializedEqual(self, value):
        self.assertEqual(self.serialize_round_trip(value), value)

    def assertSerializedIs(self, value):
        self.assertIs(self.serialize_round_trip(value), value)

    def assertSerializedFieldEqual(self, value):
        new_value = self.serialize_round_trip(value)
        self.assertEqual(value.__class__, new_value.__class__)
        self.assertEqual(value.max_length, new_value.max_length)
        self.assertEqual(value.null, new_value.null)
        self.assertEqual(value.unique, new_value.unique)

    def test_serialize(self):
        """
        Tests various different forms of the serializer.
        This does not care about formatting, just that the parsed result is
        correct, so we always exec() the result and check that.
        """
        # Basic values
        self.assertSerializedEqual(1)
        self.assertSerializedEqual(None)
        self.assertSerializedEqual(b"foobar")
        self.assertSerializedEqual("föobár")
        self.assertSerializedEqual({1: 2})
        self.assertSerializedEqual(["a", 2, True, None])
        self.assertSerializedEqual(set([2, 3, "eighty"]))
        self.assertSerializedEqual({"lalalala": ["yeah", "no", "maybe"]})
        self.assertSerializedEqual(_('Hello'))
        # Functions
        with six.assertRaisesRegex(self, ValueError, 'Cannot serialize function: lambda'):
            self.assertSerializedEqual(lambda x: 42)
        self.assertSerializedEqual(models.SET_NULL)
        string, imports = MigrationWriter.serialize(models.SET(42))
        self.assertEqual(string, 'models.SET(42)')
        self.serialize_round_trip(models.SET(42))
        # Datetime stuff
        self.assertSerializedEqual(datetime.datetime.utcnow())
        self.assertSerializedEqual(datetime.datetime.utcnow)
        self.assertSerializedEqual(datetime.datetime.today())
        self.assertSerializedEqual(datetime.datetime.today)
        self.assertSerializedEqual(datetime.date.today())
        self.assertSerializedEqual(datetime.date.today)
        # Classes
        validator = RegexValidator(message="hello")
        string, imports = MigrationWriter.serialize(validator)
        self.assertEqual(string, "django.core.validators.RegexValidator(message=%s)" % repr("hello"))
        self.serialize_round_trip(validator)
        validator = EmailValidator(message="hello")  # Test with a subclass.
        string, imports = MigrationWriter.serialize(validator)
        self.assertEqual(string, "django.core.validators.EmailValidator(message=%s)" % repr("hello"))
        self.serialize_round_trip(validator)
        validator = deconstructible(path="custom.EmailValidator")(EmailValidator)(message="hello")
        string, imports = MigrationWriter.serialize(validator)
        self.assertEqual(string, "custom.EmailValidator(message=%s)" % repr("hello"))
        # Django fields
        self.assertSerializedFieldEqual(models.CharField(max_length=255))
        self.assertSerializedFieldEqual(models.TextField(null=True, blank=True))

    def test_simple_migration(self):
        """
        Tests serializing a simple migration.
        """
        migration = type(str("Migration"), (migrations.Migration,), {
            "operations": [
                migrations.DeleteModel("MyModel"),
                migrations.AddField("OtherModel", "field_name", models.DateTimeField(default=datetime.datetime.utcnow))
            ],
            "dependencies": [("testapp", "some_other_one")],
        })
        writer = MigrationWriter(migration)
        output = writer.as_string()
        # It should NOT be unicode.
        self.assertIsInstance(output, six.binary_type, "Migration as_string returned unicode")
        # We don't test the output formatting - that's too fragile.
        # Just make sure it runs for now, and that things look alright.
        result = self.safe_exec(output)
        self.assertIn("Migration", result)

    def test_migration_path(self):
        test_apps = [
            'migrations.migrations_test_apps.normal',
            'migrations.migrations_test_apps.with_package_model',
        ]

        base_dir = os.path.dirname(os.path.dirname(__file__))

        for app in test_apps:
            with app_cache._with_app(app):
                migration = migrations.Migration('0001_initial', app.split('.')[-1])
                expected_path = os.path.join(base_dir, *(app.split('.') + ['migrations', '0001_initial.py']))
                writer = MigrationWriter(migration)
                self.assertEqual(writer.path, expected_path)